1. Field of the Invention
The present invention relates generally to broiler systems for the rapid cooking of food products, and more particularly to a broiler system combining different kinds of heating methods and including a novel compressed air system and heating element combination which guides and directs heat onto food product in the cooking chamber. The system is adapted for cooking a variety of food products through the combination of magnetic induction, radiant, and convection heat.
2. Discussion of Related Art including Information Disclosed under 37 CFR §§1.97, 1.98
To prepare certain foods, such as pizzas, hamburger patties, sausages, hot dogs, chicken and fish fillets, and the like, as well as their respective buns, high output commercial food purveyors (i.e., fast food restaurants) utilize cooking systems (usually broilers) that rapidly and continually cook the food products. The systems typically comprise a housing having a horizontal conveyor for moving food product from an input end to an output end. During the cooking process the food passes between a number of spaced-apart cooking elements, typically either electric resistance elements or gas burners. As may be readily appreciated, the profitability of utilizing such a system hinges on a number of factors, including the rapidity and efficiency with which the food product can be cooked, the minimization of energy and/or fuel utilized in cooking, the ease with which the system can be serviced and cleaned, the quality (and therefore desirability) of the cooked food products, and so forth.
The present invention improves on prior art broiler systems by providing a system which includes a combination of magnetic induction heating element, gas or electric heating elements, a compressed air system which distributes and directs forced air through an plenum disposed above the cooking food product into the cooking chamber, and heat reflecting surfaces (i.e., radiant heat/infrared heating elements) on both the underside of the air plenum and on other structures within the cooking chamber. The combination multi-stage cooking system provides rapidly cooked food products of uniform doneness, high quality, and moisture content.
Several rapid cooking broiler systems have been developed for use in the fast food industry, including those described in the following U.S. patents and patent applications.
U.S. Pat. No. 4,936,286, to Baker, discloses a broiler system having at least two side-by-side broiling conveyors, and broiler units mounted adjacent to the conveyors extending across the combined widths of the two conveyors. To permit different heating conditions on the two conveyors while still permitting the broiler units to be interchangeable and made of interchangeable parts, a broiler unit is provided with a shield which blocks off the heated face of the broiler unit where the broiler unit faces one of the conveyors. The shield preferably carries a portion which extends towards the adjacent edges of two conveyors to prevent lateral heat radiation between the conveyors.
U.S. Pat. No. 4,188,868, to Baker et al, shows a broiler system having a food passageway restricted by baffles, including an entrance shield of heat-reflecting material formed as a fitting over the entrance burner housing and including a baffle sheet extending from the entrance burner housing through most of the gap toward the entrance opening, and an exit shield of similar heat-reflecting material formed as a fitting over the exit burner housing and having a baffle sheet extending from the exit burner housing through most of the gap toward the exit opening. In addition, there is an intermediate shield including a horizontal sheet of similar material resting on adjacent burner housings and having a vertical sheet depending from said horizontal sheet. The entrance shield, the exit shield and the intermediate shield define the upper limits of the passageway through the burner and tend to reflect heat away from the entrance and exit openings and to limit air circulation within and through the passageway.
U.S. Pat. No. 4,121,509, to Baker et al., teaches a housing having a passageway through which a continuous food conveyor operates, taking food products from an inlet end to an outlet end. Within the passageway the food products are exposed to infrared radiation from heaters, hot air blown from a fan through a supply duct and through groups of nozzles onto the patties, and steam or hot water vapor provided through the air supply. By using three different types of heat supply—direct infrared radiation, warm air, and water vapor—the system provides a quickly cooked food product having a relatively high moisture content.
U.S. Pat. No. 3,987,718 to Lang-Ree et al., discloses a hamburger patty and bun cooker having a frame supporting lower and upper heated platens. A product conveyor, typical of such systems, moves food product from the inlet to the outlet. At least one of the platens is provided with a low-friction layer between it and an advancing patty. The layer is constituted by jets of hot air discharged over the platen surface or by a Teflon-coated thin, metal foil sheet or by a Teflon-carrying thin, fiber glass sheet, the sheets being readily changeable. Bun portions for the individual patties are advanced on the same frame in paths parallel to the hamburger patties by comparable endless conveyors and are heated by individual platens on the frame as the bun portions advance.
U.S. Pat. No. 5,277,924 to Padilla, teaches a conveyorized pizza cooking system that includes a radio frequency chamber located downstream of the pizza loading station for proofing pizza dough shells using RF energy in the radio frequency chamber on the conveyor. It does not include a magnetic induction plate.
U.S. Pat. Appl. Ser. No. 2005/0256774 by Clothier et al, teaches a food preparation system that conveys food during cooking and includes at least one heating station, which may include one or more induction cooktops.
U.S. Pat. No. 6,915,734 to Torghele et al, teaches an automated pizza production oven in which an automatically prepared pizza is baked in one of multiple ovens. One unit may be an induction unit, although such a unit is not shown in combination with other kinds of heating methods.
U.S. Pat. No. 4,164,591 to Ahlgren et al, disclose a pizza oven having a track for conveying pizzas through a cooking chamber with multiple oven types, including convection oven with radiant heat and a toasting zone. An intermediate section includes a baking zone which is not directly exposed to heating elements but where heating is by convection from the heater elements.
While some of the foregoing publications teach the use of magnetic induction for heating and/or cooking pizza, none show a cooking system in which magnetic induction is employed as one stage of a multi-stage cooking process that also utilizes convection and/or radiant heating. However, the foregoing patents do reflect the current state of the art of which the present inventors are aware. Reference to, and discussion of, these patents is intended to aid in discharging the respective Applicants' acknowledged duties of candor in disclosing information that may be relevant to the examination of claims to the present invention. However, it is respectfully submitted that none of the above-indicated patents and patent applications disclose, teach, suggest, show, or otherwise render obvious, either singly or when considered in combination, the invention described and claimed herein.